Using an electric mixer, beat the peanut butter and agave until light. Add the warmed honey, mascarpone, amaretto, and salt and continue beating until very light and fluffy.

Put about ¼ cup of this mixture into the bottom of 6 small bowls and refrigerate.

Make a slurry by blending the cornstarch into the coffee.
Heat the milk and half-&-half over low to medium heat in a saucepan on top of the stove.

Using a whisk, blend in the sugar, and salt and heat until the mixture just starts to steam. Blend in the bittersweet chocolate and whisk until it melts, then whisk in the cocoa. The mixture should be steaming but not boiling.

Whisk up the cornstarch slurry again and then pour in a little of the hot cream mixture (about ¼ -1/2 cup) into the slurry and whisk to blend well. Pour the slurry mixture back into the hot pudding and continue to whisk and cook until the pudding thickens to almost the desired consistency.

Remove the pan from the heat and continue whisking for several minutes to keep the pudding smooth. Ladle about ½ cup of chocolate pudding over the peanut butter layer in each serving dish. Cover with plastic wrap and refrigerate. The dish should be wide enough and the layers thin enough that a spoonful contains both pudding flavors.

Thanks for the nice comments from hardlikearmour, Sagegreen, and JoanG. I made this again, using 3 cups of whole milk (instead of 1 cup milk and 1 cup half and half), also increasing the sugar from 1/2 to 3/4 cup. This change yielded a better ratio of chocolate pudding to peanut honey creme. One other correction, the listing for 1 tablespoon cornstarch should have been 1 tablespoon unsweetened cocoa. I also increased the cocoa from 1 to 2 tablespoons in the revised version.